The present invention relates to a device by which strips of limited transverse dimensions are spliced automatically.
Conventionally, narrow tear strips of the type in question are fixed to the inner face of wrappers enveloping packs of cigarettes, candy and similar products, in cases where it is wished to establish a predetermined and clearly defined breaking line in the wrapper.
Such strips are supplied in bulk reels which hold a notable quantity of material, precisely by reason of the limited dimensions of the strip itself. When utilizing a traditional wrapping machine typified by operation at relatively low speed, therefore, it happens that the duration of the reel of tear strip is long compared to that of the roll of wrapping material, and the frequency with which replacement becomes necessary is decidedly low compared to the frequency with which the rolls of wrapping material need to be replaced. With the need for changeover occurring so infrequently, it would be considered acceptable to stop the wrapping machine for a time sufficient to replace the reel of strip material by hand, as this would not significantly affect either the overall operating speed of the machine, or, by extension, its overall efficiency.
Successive increases in the operating speeds of wrapping machines have been accompanied by a need to cut this down time, given that any pause, even of a few seconds, can detract significantly from the overall efficiency of the machine.
It will be noted, in fact, that variations in the overall efficiency of such machines become more evident as the operating speed increases. In addition, it becomes increasingly difficult for an operator to change reels in a very short time without errors occurring, especially considering the precision required and the exiguous transverse dimensions of such strips, of which the width may vary between 1, 2 and 6 mm, and is typically 2 mm or thereabouts.
The object of the present invention is to provide a device by which strips of the type in question can be spliced automatically and with a high degree of precision.